Messages in this thread | | | Subject | Re: [PATCH v5 2/2] Add Intel LGM soc DMA support. | From | Peter Ujfalusi <> | Date | Fri, 28 Aug 2020 14:17:06 +0300 |
| |
Hi,
On 27/08/2020 17.41, Reddy, MallikarjunaX wrote: >>>>> + >>>>> + dma_dev->device_alloc_chan_resources = >>>>> + d->inst->ops->device_alloc_chan_resources; >>>>> + dma_dev->device_free_chan_resources = >>>>> + d->inst->ops->device_free_chan_resources; >>>>> + dma_dev->device_terminate_all = >>>>> d->inst->ops->device_terminate_all; >>>>> + dma_dev->device_issue_pending = >>>>> d->inst->ops->device_issue_pending; >>>>> + dma_dev->device_tx_status = d->inst->ops->device_tx_status; >>>>> + dma_dev->device_resume = d->inst->ops->device_resume; >>>>> + dma_dev->device_pause = d->inst->ops->device_pause; >>>>> + dma_dev->device_config = d->inst->ops->device_config; >>>>> + dma_dev->device_prep_slave_sg = >>>>> d->inst->ops->device_prep_slave_sg; >>>>> + dma_dev->device_synchronize = d->inst->ops->device_synchronize; >>>>> + >>>>> + if (d->ver == DMA_VER22) { >>>>> + dma_dev->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES); >>>>> + dma_dev->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES); >>>>> + dma_dev->directions = BIT(DMA_MEM_TO_DEV) | >>>>> + BIT(DMA_DEV_TO_MEM); >>>>> + dma_dev->residue_granularity = >>>>> + DMA_RESIDUE_GRANULARITY_DESCRIPTOR; >>>>> + } >>>> So, if version is != DMA_VER22, then you don't support any direction? >>>> Why register the DMA device if it can not do any transfer? >>> Only dma0 instance (intel,lgm-cdma) is used as a general purpose slave >>> DMA. we set both control and datapath here. >>> Other instances we set only control path. data path is taken care by dma >>> client(GSWIP). >> How the client (GSWIP) can request a channel from intel,lgm-* ? Don't >> you need some capabilities for the DMA device so core can sort out the >> request? > client request channel by name, dma_request_slave_channel(dev, name);
clients should use dma_request_chan(dev, name);
If the channel can be requested via DT or ACPI then we don't check the capabilities at all, so yes, that could work.
>>> Only thing needs to do is get the channel, set the descriptor and just >>> on the channel. >> How do you 'on' the channel? > we on the channel in issue_pending.
Right. Basically you only prep_slave_sg/single for the DMA_VER22? Or do you that for the others w/o direction support?
For the intel,lgm-* DMAs you only call issue_pending() and probably terminate_all?
Interesting setup ;)
- Péter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
| |